The transverse arms of a cruciform church, usually facing north and south. Since the transept precedes the apse, the most sacred part of the church, it becomes a space where religious decorations that inspire devotion can be included. Examples are Cimabue's frescoes (after 1279) from the Passion, Apocalypse, and lives of Sts. Peter and Paul in the transept of the Upper Church of San Francesco, Assisi, and Pietro Lorenzetti's (1325-1330) Passion scenes in San Francesco's Lower Church. At times, transepts also contain chapels with holy relics or tombs, among the most notable Renaissance examples being Filippo Brunelleschi's Old Sacristy (1421-1428) and Michelangelo's New Sacristy (1519-1534), both radiating from the transept in the Church of San Lorenzo, Florence, which function as the funerary chapels of members of the Medici family.
Historical dictionary of Renaissance art. Lilian H. Zirpolo. 2008.